Seam for woven metal or plastic fabric for papermaking machines



Jan. 30, 19,68 H. c. HALLER 3,366,355

SEAM FOR wovsu METAL on PLASTIC FABRIC FOR PAPERMAKING MACHINES Filed Oct. 13, 1965 r Y s Sheets-Sheetl INVENTOR HERBERT C. HALLER BY MMW ATTORNEY Jan. 30, 1968 H. c. HALLER 3,366,355

SEAM FOR WOVEN METAL OR PLASTIC FABRIC FOR PAPERMAKING MACHINES Filed Oct. 13, 1965 3 Sheets-Sheet 2 jl'yni WOVEN- WEFTS SEAM- WEFTS KNVENTQR I HERBERT c. HALLER ATTORNEY ,1968 H. c. HALLER' 3,36

SEAM FOR WOVEN METAL OR PLASTIC FABRIC FOR PAPERMAKING MACHINES Filed Oct. 13, 1965 I 3 Sheets-Sheet I5 Z 6 60. 5

ig9n6' I 2 WARPS 5 SEAM- WEFTS SEAM- WEFTS WOVEN 4 WOVEN- 4 WEFTSV WEFTS \NVENTOR HERBERT C.'HALLER ATTORNEY United States Patent 3 366,355 SEAM FOR WOVEN lVhiTAL 0R PLASTIC FABRIC FOR PAPERMAKING MACIHNES Herbert C. Haller, Appleton, Wis., assignor to Appleton Wire Works Corporation, Appleton, Wis., a corporation of Wisconsin Filed Oct. 13, 1965, Ser. No. 495,426 5 Claims. (Cl. 245-) This invention relates to a seam construction for joining the ends of a length of woven fabric, usually into an endless belt, which fabric comprises interwoven spaced warp and weft threads; endless belts formed with the seam of this invention are intended principally for various uses in connection with papermaking machines and for converting operations, such as those which require the application of suction or vacuum through a woven belt.

The fabrics with which the seam of this invention are primarily intended to be used have warp and weft threads which are made of metal or plastic, either in the form of wire, monofilaments or thin threads twisted into cableform. The terms warp and weft are employed herein in the usual sense in which they are used in the Fourdrinier weaving art in which, when fabric of the specified type is woven on a loom, the individual warps are strung longiturinally of the loom through a set of heddles and are raised and lowered by movement of the heddles in accordance with the desired weave pattern to form the so-called triangular shed. The weft material is carried in a shuttle which is caused to move transversely of the loom to pass through the sheds formed by raising and lowering the warps, after which a lay is actuated to beat the wefts into the apex of the sheds or the beat line.

One of the principal objects of this invention is to provide a new seam construction for joining woven fabric of the type described into an endless belt or loop for use on papermaking machines; another is to provide a seam which is stronger than some previously-used seams and more nearly approaches the strength of the fabric it is used to join; and still another is to provide a seam which has a good appearance. A more specific object is to provide a seam construction for joining a length of woven fabric into an endless belt wherein the seam comprises a band of crimped seam-wefts and the ends of the warps in the length of woven fabric are joined to the seam-weft in a specific sequence. Other objects should become apparent from the following description.

As set forth in detail hereinafter, this invention provides a seam construction to form a loop from a length of woven fabric which has interwoven spaced warp and weft threads in which the warps have ends projecting beyond the last weft at each end of the length of fabric. A band of seam-wefts is established to develop the seam and to become wefts in the joined fabric after the seaming is completed. The projecting ends of the warps of the length of woven fabric are then joined to the seam-wefts in a controlled pattern wherein each end of one warp is joined to a first edge of the band of seam-wefts, each end of the adjacent warp is joined to the opposite edge of the seam-wefts, and each end of the next adjacent warp is joined to the center portion of the seam-wefts. The portions of the warps which cross seam-wefts are woven therewith in the same pattern as the warps were interwoven with wefts in originally joining the length of fabric on a weaving loom. It has been discovered that, surprisingly, the new seam construction now disclosed provides a seam of increased strength as compared to other seam constructions commonly used in the papermaking field, as is brought out in the following description by comparing its strength to that of other constructions. Provision is also made for applying an adhesive coating over the seam after it is formed in order to further enhance its strength. All of this is described in detail with reference to the drawings, wherein:

FIG. 1 is a perspective view of an endless belt joined with the seam of this invention;

FIG. 2 is a view of a longitudinal section of the belt of FIG. 1 showing details of the warp configuration;

FIG. 3 is a view of a transverse section of the belt of FIG. 1 showing the weft configuration;

FIG. 4 is a schematic view, with a portion broken away, of the seam construction of this invention;

FIG. 5 is a view of pre-crimped seam-welt used in the seam of this invention; and

FIGS. 6-8 are schematic views of some known constructions to which the strength of the seam of this invention is compared.

In FIG. 1, there is shown an endless belt 1 formed from a length of fabric having its opposite ends joined along a seam 2 constructed in accordance with this invention. The belt includes warps 3 inter-woven with wefts 4, the warps extending longitudinally of the belt and the wefts transversely, which were woven together on a loom in the manner described above. In order to distinguish them from the seam-wefts described below, the wefts 4 that are woven with the warps on a loom will be referred to as the woven-wefts. After the length of fabric is woven, the warps 3 have each of their ends extending beyond the last woven-weft 4 at each end of the length of fabric and these extending warp ends are attached along the seam 2 in the manner described hereunder. During the weaving of the fabric, the warps 3 become crimped as illustrated in FIG. 2 so as to have knuckles 5 and the woven-welfts 4 likewise become crimped so as to have knuckles 6 as indicated in FIG. 3. The warps 3 and woven-wefts 4 can be woven together in any repeated pattern in use in the papermaking field, such as the plain weave in which each weft passes successively under one warp and then over the next warp, or the socalled twill (sometimes referred to as the semitwi1l or twilled) weave each weft passes over two warps and then under the next warp, or a pattern such as that described in United States Patent 3,143,150 wherein each weft passes alternately over a pair of warps and then under a pair of warps. The seam of this invention can be used with any of these weaves, as well as other weaves which may be used.

Turning now to FIG. 4, the seam 2 joining a length of fabric into the belt 1 comprises a plurality of seam-wefts 8 added to the fabric after it has been woven and to which the ends of each warp 3 in the fabric are joined. The seam-wefts 8 are spaced apart to correspond to the spacing of the woven-wefts 4 so that the seam 2 will properly fit in with the balance of the fabric. Both ends of each warp in the length of fabric are joined to the seam-wefts in a prescribed pattern, and that portion of each warp which crosses seam-wefts is woven therewith in the same pattern with which the warps were woven with the woven-wefts 4 on the loom. In order to clarify the showing in FIG. 4, the lowermost portion of the warps have been shaded while the upper portions have been left unshaded. The joints between the warp ends and seam-wefts are shown by small circles or semicircles 11.

The following pattern is used to form the seam 2 of this invention: the left-hand warp shown in FIG. 4, warp 311, has both of its ends terminating at the center seam-weft So; each end of the next warp, warp 3b terminates at seam-weft 817 along a first edge of the band of seam-wefts; and then the next adjacent warp 3c has both of its ends terminating at seam-weft at the opposite edge of the band of seam-wefts. This sequence is repeated across the entire width of the fabric until all warps terminate at the seam-wefts in the desired pattern. The ends of the warps can be joined to their respective seamwefts, as by adhesive bonding in the case of plastic materials or soldering in the case of metal materials.

It is to be understood that the two ends of a warp that are aligned and terminate with one another, so as to have a mating relationship at the seam, need not be of the identical warp throughout the length of fabric. For example, some warps may be trimmed to terminate at the edge of the fabric so that the fabric does not present identical warps at each end. Also, the seam may join ends of two different fabrics, to obtain a single fabric of extended length, rather than a closed loop. In these latter cases, the ends of the warps which terminate along the ends of the length of fabric (i.e., the marginal portions parallel to the seam) are to be joined to the seam-wefts in the prescribed manner.

After all of the warps have been joined to the seamwefts, the ends of the seam-wefts projecting beyond the outermost warps are trimmed off flush therewith and joined to the warps by any of the methods described below.

The seam-wefts 8 are pre-crimped, that is they are crimped to have knuckles before they are added to the fabric. As shown in FIG. 5, a seam-weft 8 is cn'mped to have knuckles 6a which correspond to the knuckles 6 in the woven-wefts4. One way of establishing this pre-crimping is to weave a length of fabric using the same pattern and spacing of warp and wefts as is desired in the final belt, remove the fabric from the loom and then take out some of the wefts for use as seam-wefts; in this manner, the seam-wefts will have the same physical configuration as the woven-wefts in the completed belt.

EXAMPLE 1 This example demonstrates that the seam construction of this invention has significant strength advantages over several other seams commonly used for joining fabrics in the papermaking art. FIG. 6 depicts a portion of a length of woven fabric having the ends of its warp 3 joined along a seam 12 in which the warp ends are joined at random positions to seam-wefts 8 within the seam 12. FIG. 7 illustrates a prior art seam construction in which the ends of the warps 3 are joined along a seam 13 with the ends of each warp being joined to the seam-wefts in a repetitive pattern wherein one warp has both of its ends joined to seam-weft 8a along one edge of the seam and the ends of the next adjacent warp are joined to the seam-weft 8b along the opposite edge of the seam. In the construction shown in FIG. 8, the warps 3 have their ends joined to the seam-wefts 8 in a repetitive pattern wherein the ends of two adjacent warps are joined to the seam-weft 8a along one edge of seam 14 and the ends of a next pair of warps 3 are joined to the seam-weft 8b along the opposite edge of the seam 14. In each of FIGS. 6-8, the ends of the warps are indicated by the double arrowheads. Fabric woven with plastic (a polyester, polyethylene terephthalate) monofilaments for warps and wefts were joined by the scams 2, 12, 13 and 4 shown in FIGS. 4 and 6-8 respectively. All the fabrics were woven with the same number of warps and wefts per inch, each fabric being woven in a 16 mesh count in which there were 16 warps and 16 wefts per inch. (Whenever used herein, the number of warps/ inch is measured in the transverse direction and the number of wefts/inch is measured in the longitudinal direction.) The same pattern for interweaving the warps and wefts was used for all fabrics and the same size plastic monofilament was used in each case. The tensile strength of each seam was measured with standard testing equipment, yielding the following results:

Pounds/inch of seam Seam of FIG. 6 60 Scam of FIG. 7 115 Seam of FIG. 8 119.6 Seam of FIG. 4 260 As is demonstrated in the above results, the seam constructed according to this invention, the seam of FIG. 4, had a tensile strength substantially in excess of the three prior art constructions shown in FIGS. 6-8. The increase was very substantial, the seam of FIG. 4 being more than twice as strong as the seams of FIGS. 7 and 8 and being over four times as strong as the seam of FIG. 6 (and that the ends of the warps were snipped). The woven fabric outside of the seam area had an original tensile strength of about 360 lbs. per inch of width; thus it can be seen that the seam of FIG. 4 more nearly approached the original fabric strength than the other three seams described above. In the above seams, the warp ends were snipped after the warps were properly arranged with respect to the seam-wefts; the ends can also be chiseled off, but snipping has been found to result in slightly higher (about 5 to 10%) seam strengths.

EXAMPLE 2 The strength of the seam construction disclosed herein can be increased by coating the finished seam with an adhesive. Many types of adhesives are suitable, epoxy adhesives and nitrile rubber adhesives being specific examples of useful materials. The adhesives can be applied over the entire seam area, subjected to a blast of compressed air to blow out the excess adhesive which might be clogging up the open areas of the fabric, and then allowed to dry. Preferably, an adhesive that bonds at room temperature is preferred to one which requires heat so as to prevent problems of shrinkage brought about by local heating along the seam area, particularly when us-- ing plastic warps or wefts. The four seams described above in Example 1 were coated with a nitrile rubber (Pliobond) adhesive and their tensile strengths were measured in the same manner, with the following results:

Lbs/inch Seam of FIG. 6 Seam of FIG. 7 Seam of FIG. 8 157.3 Seam of FIG. 4 285 EXAMPLE 3 result in increased life of the belt in which the seam is used.

There is thus being described a new seam construction to be used with woven fabrics for joining the fabric into endless belts, which seam has a higher strength than some other prior art seams used in the same art and an in-.

creased fatigue life under flexing conditions. The seam of this invention can be used with woven fabrics which have either metal or plastic warps and wefts. The new seam also presents an excellent visual appearance and can be made so as to be barely visible to the naked eye. The seam can be formed by various manufacturing techniques; for example, one method is to establish the plurality of seam-weft along a workbench with their opposite ends in movable frames, place the ends of the length of fabric having portions of the warps extending beyond the last woven-weft at each end of the fabric on opposite sides of the seam-wefts and then arrange the exposed portion of each warp across the seam-wefts in the desired relation, with the movable frames supporting the seam-wefts being moved after each particular warp is in place so as to prepare for reception of the next warp and enable the warps and seam-wefts to be arranged in the weave pattern used in the length of fabric. The warp ends then can be severed at the desired terminal positions as described above, following which the warp ends can be joined to the seam-wefts in any desired manner, as by adhesive binding in the case of plastic materials or soldering in the case of metal materials.

This invention calls for the development of the seam by adding a plurality of seam-wefts to the fabric; the actual number of seam-wefts added can vary over a wide range, although for most purposes best results are obtained when the number of seam-wefts added is at least about one and one-half times the number of Woven-wefts/inch in the length of fabric being joined by the seam. Good results also are obtained with a greater number of seam-Wefts. Present experience indicates that 1 /2 to 2 /2 times the number of wovenwefts/inch in length of fabric is a satisfactory operating range for most commercial utilization of the present invention. Thus, a seam of this invention used in joining a length of fabric having thirty-six warps per inch (transverse direction) and thirty woven-wefts per inch (longitudinal direction) could use about forty-five to fifty seamwefts which would be in the lower part of a range of 1 /2 to 2 /2, and in joining a length of fabric having sixteen warps and sixteen wefts per inch, thirty-six seamwefts can be added to establish the seam, which would be in the upper pant of a range of 1 /2 to 2 /2. The wanp end-s need not terminate precisely along the seam-wefts on each edge of the seam, and good results have been obtained where the warp ends terminate on the second or third seam-Weft in from the outermost seam-weft at each edge. It is generally desirable that the Warp ends terminating at the center of the seam do so on the middle seam-weft. However, the first and second edge portions and center portion of the plurality of seam-wefts in the seam along which the warp ends terminate can each contain several seam-wefts, from about 1-3 seam-wefts now considered optimum for these portions, and with there being other seam-wefts (along which no warp ends terminate) between these three portions.

Belts or loops of fabric joined with the seam of this invention have been used on papermaking machines as the moving belt for the paper-making surface in a Fourdrinier machine, and as a covering for the press rolls in a papermaking machine. Such belts or loops have also been used in connection with converting processing as a conveyor belt for transporting paper through converting operations where a vacuum was drawn through the belt to hold paper on the belt, and as a dry-forming belt wherein light, flufiy cellulosic particles were deposited on a belt moving through a chamber and a suction was drawn through the belt to form the particles into a sheet. Other uses, principally in the paperrnaking and converting fields are envisioned, particularly uses involving the creation of a pressure difierential across a moving belt to form material into a sheet or to hold material onto the belt.

While the preceding description has been made with reference to several specific forms of this invention in order to clearly set forth its general principles to those skilled in the art, it is expected that changes can be made in the described embodiments and that other embodiments of the invention can be devised for utilizing the present invention. And, While the embodiments shown relate to closed loops, the invention can be used for other seaming purposes. -It is understood that it is intended to cover all such changes which do not constitute a departure from the spirit and scope of this invention.

1 claim:

1. In a length of woven fabric having its ends joined by a seam to form a loop, said length of fabric comprising spaced warps interwoven with spaced wefts (here inafter referred to as Woven-wefts) in a selected repeated pattern and said woven-wefts being crimped during the weaving of the fabric to have knuckles, in which fabric the warps and woven-wefts are metal or plastic, the combination wherein:

the seam comprises a plurality of seam-wefts added to the length of fabric after it has been woven, each seam-weft being formed before it is added to the length of the fabric to have knuckles which correspond to the knuckles in the woven-wefts and each seam-weft being spaced to correspond to the spacing of the woven-wefts, the plurality of seam-wefts having a first edge portion and a second edge portion on opposite sides of a center portion; and

the ends of each warp of the length of fabric terminate along the seam-wefts to form the length of fabric into a loop, said ends arranged in a repeating sequence wherein the ends of a first warp terminate at the first edge portion of the seam, the ends of a second warp adjacent the first terminate at the second edge portion of the seam, and the ends of a third warp adjacent the second terminate at the center portion of the seam, with the portion of each warp which crosses seam-wefts being interwoven therewith in the same pattern as the warps were interwoven with the woven-wefts.

2. An article as defined in claim 1 wherein the number of seam-we-fts is \at least about 1 /2 times the number of woven-wefts/inch in the length of fabric.

3. An article as defined in claim 2 wherein the first edge portion, second edge portion and center portion of the plurality of seam-wefts each comprises about 1 to 3 seam-wefts.

4. An article as defined in claim 1 wherein an adhesive coating is disposed over the seam.

5. In a seam that joins two ends of a fabric having spaced warps interwoven with spaced wefts, the combination comprising:

a plurality of seam-wefts that are crimped to have knuckles corresponding to the spacing between warps, and which are spaced from one another to correspond to spacing between other Wefts of the fabric; said seam-wefts presenting a center portion for the seam and first and second edge portions for the seam that are on opposite sides of the center portion;

the warps at the two ends of said fabric being arranged to terminate along the seam-wefts in a repeated sequence wherein for one end of the fabric a first warp terminates at the first edge portion of the seam, a second warp terminates at the second edge portion of the seam, a third warp terminates at the center portion of the seam, and such sequence is then repeated, and wherein for the other end of the fabric the warps are aligned with the warps of said one end and terminate to mate with the terminations of the warps of said one end; and

portions of the warps which cross the seam-wefts are interwoven therewith.

References Cited UNITED STATES PATENTS RICHARD J. HERBST, Primary Examiner. 

1. IN A LENGTH OF WOVEN FABRIC HAVING ITS ENDS JOINED BY A SEAM TO FORM A LOOP, SAID LENGTH OF FABRIC COMPRISING SPACED WARPS INTERWOVEN WITH SPACED WEFTS (HEREINAFTER REFERRED TO AS WOVEN-WEFTS) IN A SELECTED REPEATED PATTERN AND SAID WOVEN-WEFTS BEING CRIMPED DURING THE WEAVING OF THE FABRIC TO HAVE KNUCKLES, IN WHICH FABRIC THE WARPS AND WOVEN-WEFTS ARE METAL OR PLASTIC, THE COMBINATION WHEREIN: THE SEAM COMPRISES A PLURALITY OF SEAM-WEFTS ADDED TO THE LENGTH OF FABRIC AFTER IT HAS BEEN WOVEN, EACH SEAM-WEFT BEING FORMED BEFORE IT IS ADDED TO THE LENGTH OF THE FABRIC TO HAVE KNUCKLES WHICH CORRESPOND TO THE KNUCKLES IN THE WOVEN-WEFTS AND EACH SEAM-WEFT BEING SPACED TO CORRESPOND TO THE SPACING OF THE WOVEN-WEFTS, THE PLURALITY OF SEAM-WEFTS HAV- 